Conventionally, in a seat belt device of this type, when there is a possibility of collision, a seat belt (webbing) is retracted by the electric actuator before collision, and then the possibility of collision disappears, the seat belt is put back to the state before the possible collision was sensed, and when the collision occurs, the seat belt is retracted by the pre-tensioner (for example, refer to Patent Document No. JP-A-2003-191819).